Echinococcosis is a parasitic disease that occurs in two main forms in humans: cystic echinococcosis (also known as hydatidosis) and alveolar echinococcosis, caused by the tapeworms Echinococcus granulosus and E. multilocularis, respectively.

Dogs, foxes and other carnivores harbour the adult worms in their intestine and pass the parasite eggs in their faeces. If the eggs are ingested by humans, they develop into larvae in several organs, more frequently the liver and lungs. Both cystic and alveolar echinococcosis are characterized by asymptomatic incubation periods that can last many years until the parasites grow to an extent that triggers clinical signs.